| Slopes, earthquake and volcano are three major geological disasters, which do great harm to people's lives, property and safety. To this day, the studies of the stability have experienced a period of from qualitative analysis, half-quantitative analysis, quantitative analysis to uncertain analysis. Because of the complexities of geological condition, and other uncertain influence factors, it is difficult for us to grasp the theory of slopes completely. No method can valuate the slope's deformation procedure completely, accurately and objectively, so the slope stability still need deep exploration and .studies.In this essay, the research background is set in the high slopes of Long Jiang grand bridge foundation area which is on the Baoshan-Tengchong Highway, and it is based on the slope geological structure condition, the physical and mechanical parameters of rock and soil and the formation and evolution of the slope. First, the method of particle flow, are used to simulate the evolution mechanism of rock and soil slope and to analyze different kinds of influence factors in the slope stability. According to these analysis, the slope damage mechanism are disclosed. Second, by virtue of sufficient collection of domestic and foreign assess methods of slope stability. different kinds of stability methods of qualitative analysis, such as limit equilibrium(GLE general slice method), finite element strength reduction and historical topography and so on, are used to analyze a certain complex high slope, and to evaluate slope stability from different points of view and to analyze different compatibilities of those mehtods.The research by particle flow method shows: for rock slopes, the influence of cohesion on slope stability is more severe than that of internal friction angle. The stability of rock slope is controlled by the combination of free faces, structural planes and soft layers, so are the unloading fractures and joints; the damage of loose rock slope has close connection with its particle shape and size, the bigger of the particle group, the higher of the whole stability, the less of the part stability; if the particles are smaller and its gradation is continuous, the local stability will be greater, and the whole stability will be controlled by rock and soil physical and mechanical properties.For stability evaluations of different slope areas, ,the methods of 3D FLAC Lagrangian finite difference and Two-dimensional limit equilibrium are used. By 3D FLAC Lagrangian finite difference, the range of landslide and corresponding safety factor can be acquired. The landslide range can show the landslide's space distribution ,its size and its main sliding direction. The method of 2D limit equilibrium can be used on several sliding surfaces for finding out the corresponding safety factors, and this method can be used for acquirement of the most dangerous slide surface by its application on the different parts of the landslide, and it also can be used for a specified sliding surface. The differences of safety factor between the two methods are similar, but the safety factor by Lagrangian finite difference is larger than that of Two-dimensional limit equilibrium. The result from historical topographic evolution method is consistent with other evaluation methods.In this essay, on the basis of three qualitative analysis methods, which are Three-dimensional Lagrangian finite difference, Two-dimensional limit equilibrium, and the stability method of historical topographic evolution, the slope's safety factor and the landslide range can be acquired. Diversified evaluation methods can show the present situation of the slope stability objectively , and they provides the scientific basis for the slope reinforcement.It is hoped that the essay is helpful to the study on the slopes, and the methods in the essay could be a good reference to the complex high slopes similar to Long Jiang bridge.. |
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